Use has been made of a technique to determine the distribution in atmosphere of the so-called optically active components (aerosol, ozone, water vapor, etc.) by the brightness profiles of atmosphere on a horizon, measured from space. Developed are the PHASE eight-channel aerospace teleradiometer and laboratory equipment for its study and graduation (including the complex for an absolute graduation and collimator for reading the characteristics of the teleradiometer field of vision). The PHASE teleradiometer has been installed on board of orbital complex `Salyut-7' - `Cosmos-1686' - `Sojuz-T14' and more than 10,000 brightness profiles were obtained over various regions of the Earth.